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5 Clean Jet Fuels to Wean Planes Off Oil (& Make Tickets Cheaper)

The friendly skies are getting expensive. Airlines spent $25 billion more on fuel last year than the year before, and they're expected to spend $50 billion more than that$183 billionby the end of 2008. The military is also concerned about the high price and foreign sources of oil, and that's got it testing synthetics and more. As cheap oil fades into memory, we get an update on research into new ways to power tomorrow's airplanesand lower the cost of riding them.

MORE NEW REPORTING FROM THE ECO-FRIENDLY SKIES

Coal

The U.S. sits on some of the largest coal reserves in the world, and as oil prices surge, the Air Force is turning over 700 acres of base in Montana for a plant that will turn solid coal into liquid fuel, certifying its planes to run a 50/50 mix of the synthetic-fuel and petroleum-derived JP-8 by 2011. The need is pressing since Army and NATO fighters burn through some 4.5 billion gal. of oil each year. Coal-to-oil, while traditionally more expensive than petroleum-based fuels, has come in today's market to represent a viable--and more important, a domestic--alternative. It can be used without altering aircraft engines or pumping equipment. However, coal-to-oil fuel is not the most environmentally friendly of oil's possible replacements. The process produces carbon dioxide, a greenhouse gas, but advocates claim CO2 capture and sequestration could be possible (especially if mandated by the government). An analysis by the U.S. Department of Energy's Argonne National Laboratory in 2007 found that this fuel, even after using carbon capture and storage techniques during creation, would still produce at least 20 percent more carbon dioxide than petrol and diesel made from oil.

Biofuel

Eager to boost their public image and seeking relief from high petroleum prices, airlines are looking to biofuels to woo today's eco-conscious fliers and to eventually save cash. Virgin made headlines earlier this year as the British carrier flew a 747 from London to Amsterdam on an 80/20 mix of standard jet fuel to biofuel made from coconut and babassu oil. Air New Zealand is expected to test a mixture of biofuel derived from jatropha, a Central American plant, in the coming months, with plans to use at least one million barrels of "sustainable" fuels in the company's aircraft per year by 2013. Critics have been skeptical--reactions to Virgin's flight cited minimal reductions in carbon emissions and possible future complications as fuel feedstocks compete for space with food crops or rainforest.

Algae

The potential for algae is undeniable. The yield of oil per acre is many times that of other feedstocks; it has the ability to thrive in dirty, brackish water, and it is capable of turning pollution from power plants or sewage treatment facilities into clean fuel. And while commercial quantities of algal oil don't yet exist at the commodity prices necessitated by the airline industry, heavyweights like Boeing and Airbus are already investigating powering tomorrow's jets with the stuff. Airlines Jet Blue, KLM, Virgin and others are also scrambling to make a viable fuel from the slime. DARPA, the Pentagon's advanced projects agency, has also funded research to refine a replacement for JP8 jet fuel from feedstocks like algae, hoping for a cheaper, cleaner, domestically produced fuel to help gas up.

Designer Hydrocarbons

Yeast and bacteria have been producing ethanol for millennia, but a bunch of startup companies are genetically engineering the microscopic organisms to metabolize sugars into hydrocarbons--including jet fuel. Researchers are able to fine-tune the exact length of the hydrocarbon chains that the organisms produce, yielding finished fuels chemically identical to those derived from petroleum. San Francisco-based LS9 is at work on a pilot facility, while fellow Bay Area company Amyris is setting up shop in Brazil, where it plans to turn some 2 million tons of sugar into commercial quantities of diesel, gasoline and jet fuel by 2012. And while today's bugs only thrive on simple sugars, future advances in technologies that break down cellulose could open up the potential to convert anything that grows into a source of feedstock.

Solar

While it's unlikely that jumbo jets will run on solar panels anytime soon, a number of aircraft are making emissions-free flying possible, using energy from the sun to stay aloft far longer than any gas tank would allow­--perhaps even indefinitely. Last month, the British-made QinetiQ Zephyr set the record for the longest unmanned flight of any kind--82 hours and 37 minutes--powered by nothing more than sunlight. The craft operated off solar-charged batteries at night. A Swiss psychiatrist is currently at work developing a solar-powered plane to take himself and a co-pilot around the world in 2011. He made a similar journey in a propane-powered hot-air balloon in 1999. With the plane's average speed is planned to be just 42 mph, the craft is hardly set to shake up the industry. The real future of solar-powered planes is likely in HALE-UAVs (High Altitude Long Endurance Unmanned Aerial Vehicles) such as the Zephyr--providing long-term environmental monitoring or surveillance.

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Sir Richard Branson poses in front of a Virgin Atlantic Boeing 747 before it embarks on the first test flight using bio-fuel made from coconut oil. (Photograph by Ben Stansall/AFP/Getty Images)

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